1. Field of the Invention
The present invention relates generally to communication networks. More specifically, the present invention relates to apparatuses, systems and methods for allocating resources in such networks.
2. Description of the Related Art
Scheduling and resource allocation is an aspect of telecommunications technology. Developments according to the third generation partnership project (3GPP) are directed to the evolution of the radio access network. Developments according to the long term evolution of radio technology are, in some cases, directed to evolved universal terrestrial radio access networks, also known as E-UTRAN. Proposals regarding scheduling in E-UTRAN include, for example, E-UTRAN being capable of dynamically allocating resources, such as physical resource blocks (PRBs) and modulation coating schemes (MCS), to user equipment at each transmission time interval (TTI) via control channels. User equipment (UE) monitors control channels, such as L1/L2, in order to find potential allocations during downlink when downlink reception is enabled. Furthermore, radio access networks such as E-UTRAN can allocate predefined downlink resources for transmissions, such as a first hybrid automatic repeat request (HARQ) error control to user equipment. Retransmissions can be explicitly signaled via L1/L2 control channels. If the user equipment cannot identify its cell radio network temporary identifier (C-RNTI) on the control channels in the sub-frames where the user equipment has been pre-assigned resources, a downlink transmission according to a predefined allocation is assumed. The user equipment, therefore, can sometimes perform blind decoding of the predefined resources. Otherwise, in the sub-frames where the user equipment has been pre-assigned resources, if the user equipment finds its C-RNTI on the control channels, the control channel allocation overrides the predefined allocation for the transmission time interval, and user equipment does not perform blind decoding of the predefined resources.
Regarding uplink scheduling, radio access networks such as E-UTRAN can dynamically allocate the resources to user equipment at each transmission time interval via the same channels. User equipment would typically monitor the L1/L2 control channels for possible allocation for uplink transmission when downlink reception enabled. Such activity is governed by discontinuous reception (DRX). Additionally, radio access networks such as E-UTRAN can allocate a predefined uplink resource for the first HARQ transmissions and potential retransmissions to user equipment. In sub-frames where the user equipment has been pre-assigned resources, if the user equipment cannot find its C-RNTI on the L1/L2 control channels, uplink transmission according to a predefined allocation assigned to the user equipment in the TTI can be made. The network performs decoding of the predefined PRBs according to the predefined MCS. Otherwise, in sub-frames where the user equipment has been pre-assigned resources, if the user equipment finds its C-RNTI on the control channels, the control channel allocation overrides the predefined allocation for that TTI. As such, the user equipment transmission follows the L1/L2 control, not the predefined allocation. Retransmissions can be exemplarily allocated using the predefined allocation or explicitly allocated via L1/L2 control channels.
In both uplink and downlink configurations, the possibility of allocating predefined resources for the first HARQ transmissions was introduced to minimize signaling overhead for services that would require frequent scheduling, such as voice over internet protocol (VOIP).
As described above, two kinds of allocations are possible in E-UTRAN: dynamic allocations and predefined allocations for the first HARQ transmissions. Due to these two types of allocations, collisions may occur between predefined resources for the first HARQ transmission and resources allocated for retransmission. A “collision” occurs when two transmissions are supposed to take place in the same TTI—one following the dynamic allocation and the other following the predefined allocation. It may be desirable to avoid such collisions in communications networks.